US 20050264931 A1
During fabrication of a perpendicular write head in a wafer, at least two sides of a write pole are defined (e.g. by ion milling) while a third side of the write pole is protected by a masking material. At this stage, a material that is to be located in the write gap is already present between the write pole and the masking material. After definition of the write pole surfaces, a layer of dielectric material is deposited. During this deposition, the masking material is still present. Thereafter, the masking material (and any dielectric material thereon) is removed, to form a hole in the dielectric material. Next, a trailing shield is formed in the structure, so that at least one portion of the trailing shield is located in the hole, and another portion of the trailing shield is located over the dielectric material, in an area adjacent to the hole. Note that the gap material is now sandwiched between the portion of the trailing shield in the hole, and the write pole.
1. A method of fabricating a perpendicular write head in a wafer, the method comprising:
defining at least two sides of a write pole, while a third side of the write pole is protected by a masking material, wherein a gap material is located between the write pole and the masking material;
depositing a layer of dielectric material over at least one surface formed during said defining;
removing the masking material to expose the gap material, the gap material being located in a hole in the dielectric material; and
forming a trailing shield comprised of at least a first portion located in the hole, and a second portion located above the dielectric material, in an area adjacent to the hole;
wherein the first portion of the trailing shield is physically separated from the write pole by the gap material.
2. The method of
3. The method of
4. The method of
5. The method of
6. The method of
removing at least a portion of the carbon, after the chemical mechanical polishing.
7. The method of
8. The method of
said ion milling removes magnetic material in areas not protected by the masking material.
9. The method of
10. The method of
a first part that is distant from the write pole and has uniform thickness;
a second part that is located within a shadow of the masking material and has the same thickness as the first part at locations adjacent thereto but becomes gradually thinner as the write pole is reached; and
a third part that is formed on vertical sides of and over the masking material.
11. The method of
prior to forming the trailing shield, depositing a non-magnetic material to form a pseudo trailing shield at least in the hole, and reactive ion etching of the pseudo trailing shield.
12. The method of
13. The method of
chemical mechanical polishing to remove the predetermined material from at least one unwanted area.
14. The method of
cutting the wafer into rows; and
lapping to expose an air bearing surface.
15. A perpendicular write head comprising a write pole, and a trailing shield separated from the write pole, wherein at least a notched portion of the trailing shield is aligned to the write pole by a method comprised of:
defining two sides of the write pole in the presence of a masking material on top of the write pole, wherein the masking material also has two sides defined during definition of the two sides of write pole;
depositing dielectric material with the masking material still in place to cause the dielectric material to have two sides conforming to the corresponding two sides of the masking material;
removing the masking material to form a hole exposing the two sides of the dielectric material; and
depositing magnetic material for the notched portion of trailing shield into the hole formed by the two sides of the dielectric material.
16. The perpendicular write head of
17. The perpendicular write head of
18. The perpendicular write head of
19. The perpendicular write head of
20. The perpendicular write head of
The present invention is directed to magnetic recording and more specifically to a notched trailing shield for perpendicular recording.
Perpendicular write heads are well known in the art. For example, U.S. Pat. RE 33,949 granted to Mallary et al. describes a vertical recording arrangement in which a downstream magnetic shield is integrally formed with a write pole section having a tip to make up the magnetic recording head. This patent is incorporated by reference herein in its entirety. Mallary states that the face of his shield is designed to be many times as large as the face of the write pole section. Hence Mallary's shield appears to serve as a return path for the magnetic flux. In contrast, a single pole write head design uses a return path pole that is located far away, while using a trailing edge adjacent to the single pole to intercept magnetic flux fringing from the single pole. See for example, U.S. Pat. No. 5,920,449 granted to Tagawa that is also incorporated by reference herein in its entirety.
It is possible to fly longitudinal heads backwards to write perpendicular media. Such heads may have a notched pole tip. However, there appears to be no known description of how a notched trailing shield is to be fabricated for a perpendicular write head as discussed below.
During fabrication of a perpendicular write head in several embodiments of the invention, at least two sides of a write pole are defined (e.g. by ion milling) while a third side of the write pole is protected by a masking material. At this stage, a material that is to be located above the pole (also called “gap material”) is already present between the write pole and the masking material. After definition of the write pole surfaces, a layer of dielectric material is deposited. During this deposition, the masking material is still present. In some embodiments, the masking material is used as a shadow mask during dielectric deposition, so that the dielectric layer forms a valley adjacent to the masking material. Thereafter, the masking material (and any dielectric material thereon) is removed (e.g. by mechanical shearing) to form a hole in the dielectric material. This structure, of a valley with a hole therein, is used as a form into which a magnetic material is deposited to form a trailing shield or alternatively a non-magnetic material is deposited to form a pseudo-trailing shield which is later recessed from an air bearing surface followed by deposition of trailing shield material.
A trailing shield resulting from the above-described process has at least one portion of the trailing shield located in the hole, and another portion of the trailing shield is located over the dielectric material, in an area adjacent to the hole. The gap material is now sandwiched between the portion of the trailing shield in the hole, and the write pole. Note that since the same masking material that is used during definition of the write pole is also used to form the hole in which a portion of the trailing shield is located, the write pole and the trailing shield are automatically aligned to one another.
A single pole notched write head in several embodiments of the invention has a pole tip 102 (
Notched trailing shield 101 is fabricated in many embodiments of this invention starting with a structure 200 of the type illustrated in
In addition, structure 200 that is to form a single write head also includes a layer 204 of masking material (such as Durimide) and a layer 205 of photoresist that is used to etch layer 204 into an appropriate shape, of the type illustrated in
Next, the photo resist in layer 205 is stripped off, and ion milling is performed, as shown in directions 5 and 6 of
Note that the above-described ion milling defines not only the two sides of pole tip 102 but also the two sides of masking material layer 204 (and also two sides of dielectric material layer 203), thereby to make them coplanar with one another. Specifically, as illustrated in
Thereafter, the milled areas 201A and 201B of layer 201 are refilled by depositing a layer 207 of dielectric material such as alumina, e.g. by performing angled Ion Beam Deposition (IBD) which is a technique well known to the skilled artisan. During IBD, an ion beam is used to sputter alumina from a target. The plume of species sputtered from the target impinge on the substrate or wafer at an angle of between 10 and 70 degrees with respect to the wafer normal. Note that during the alumina deposition step, mask material layer 204 is still in place, and hence the profile of alumina surface being formed is affected by a shadow cast by mask material layer 204, as well as the deposition angle. Hence, mask material layer 204 acts as a shadow mask relative to a direction 7 from which alumina deposition occurs. Needless to say, the surfaces of layer 207 in contact with mask material layer 204 conform to its sides (e.g. side 204S in
Specifically, the mask material layer 204 causes layer 207 of dielectric material to be formed in a three-part profile as described next. A first part 207A is distant from pole tip 102, and is fully exposed to the deposition, so that it has uniform thickness. A second part 207B is located within a shadow of mask material 204 and hence it is not fully exposed to deposition. Hence although second part 207B is of the same thickness as first part 207A at locations adjacent thereto, second part 207B becomes gradually thinner as pole tip 102 is reached. For this reason, second part 207B forms a valley around the mask 204. Finally, layer 207 also includes a third part 207C that is formed on the almost vertical (although angled) sides of and also over the mask material layer 204.
Now referring to
At this stage, hole 208 has two sides (that are almost vertical but angled) formed of dielectric material (e.g. of layers 206 and 207) and hence hole 208's sides are also coplanar with the sides of write pole 102. Note that in order for the above-described mechanical shearing off to happen, the thickness of layers 206 and 207 is kept sufficiently small (i.e. a sufficient portion of the item to be sheared off is elevated over the surrounding region). For more details, see U.S. patent application Ser. No. 10/785,236 which was incorporated by reference above.
Next, gap material layer 203 is removed to the extent necessary. Thereafter, a layer 209 (
In some alternative embodiments, instead of depositing magnetic material (in hole 208 and in areas adjacent to hole 208) over the structure in
In one alternative embodiment, a “pseudo” trailing shield is created as described above in reference to
Thereafter, the pseudo trailing shield is recessed from the air bearing surface using reactive ion etching that is selective to the pseudo trailing shield material. (e.g. F RIE which is well known to the skilled artisan as Reactive Ion Etching using Fluorine based chemistry, and which can be used to selectively remove Ta (Tantalum), W (Tungsten) or Si (Silicon) materials). The amount of recess, Dts (
In the just-described process, optionally, a polish or CMP stop layer can be deposited prior to the magnetic material. This stop layer provides more process tolerance in the CMP (Chemical Mechanical Polishing) process. Furthermore, an adhesion promotion layer (Cr, NiCr, . . . ) could be applied prior to magnetic material deposition.
Although the present invention is illustrated in connection with specific embodiments for instructional purposes, the present invention is not limited thereto. Various adaptations and modifications may be made without departing from the scope of the invention. For example, although two or more layers (such as layers 201 and 202 shown in